The present invention relates to an elongate yarn heater for use in a false twist crimping machine.
U.S. Pat. No. 5,148,166 discloses a heating apparatus subjecting a synthetic filament yarn to advance along a zigzagged path. This known heating apparatus allows to select during construction the looping angle on the yarn guides and the total sum of looping angles on all yarn guides, without thereby affecting simultaneously the distance of the yarn path from the heated surface.
The yarn guides of the known heating apparatus contact the yarn with a curved contact surface, with the yarn guides having not only the task of smoothing the yarn path and of establishing it at a defined distance from the groove bottom. Rather, the yarn guides are also very important for the heat transfer.
It is the object of this invention to optimize in a false twist crimping machine the heat transfer of the yarn heating apparatus by a special configuration of the yarn guides.